Each BRITA cartridge lasts 2 months (other filters sold in Qoo10 lasts 1 month).
Made in Germany | Switzerland, 2-month edition (printed on box, see below).
If the BRITA box you saw from other sellers says 4 weeks, then you must change it in 4 weeks.
That is the 4-week edition meant for some countries.
If the BRITA box says 8 weeks (like those shown here, or like those sold in Metro, Tangs, etc.),
then you only need to change it in 8 weeks.
